ARLINGTON HEIGHTS, Ill. - For Hall of Fame riders like Pat Day and Jerry Bailey, Saturday is just another Breeders' Cup Day. For Harry Vega, it is the opportunity of a lifetime.

Vega, 37, will get his first Breeders' Cup mount aboard Eclipse Award winner Xtra Heat for trainer John Salzman in the Sprint. It will be the defining moment in a journeyman career that has spanned 19 years and includes more than 2,500 victories, though none of any national consequence until he joined forces with Xtra Heat.

Nine furlongs is the question, Composure is the answer. She is improving with each start. Her Oak Leaf win was thoroughly professional, her subsequent works sensational. Sired by a Belmont winner and produced by a dam who ran all day, Composure wants nine furlongs. She has not run her best race yet. She will Saturday. Storm Flag Flying is unbeaten, but only two lengths better than Santa Catarina, who is several lengths inferior to Composure. Storm Flag Flying will be overbet in her first two-turner. Appleby Gardens is the pedigree longshot. By A.P.

ARLINGTON HEIGHTS, Ill. - Bob Baffert, Carl Nafzger, and Larry Jones did not compete for the same horses at the 2001 Keeneland September yearling sale. But on Saturday, four horses those trainers plucked out of that sale 13 months ago will vie for the same prize in the $1 million Breeders Cup Juvenile Fillies at Arlington Park.

European star High Chaparral stands out. After missing the summer because of illness, he used the Arc de Triomphe as a prep, ran well for third, and figures to move forward second start back. He meets an ordinary cast of U.S. turf runners, and will be justifiably favored to drill this field at low odds. Euro-shipper Golan is the logical alternative. Though Goldan is unraced since August, trainer Michael Stoute is expert at preparing comebackers. A Group 1 winner in a modest field, Golan can win only if High Chaparral loses.

ARLINGTON HEIGHTS, Ill. - One trainer has been a six-time champion in England and has won the Breeders' Cup Turf twice. The other won 22 of Europe's 78 Group 1 races in 2001 and is expected to win training titles in England and Ireland this year.

The presence of horses trained by Michael Stoute and Aidan O'Brien have not made it easy on the American team in Saturday's $2 million Breeders' Cup Turf at Arlington Park.

The Ballydoyle-Coolmore-O'Brien team arrived at Arlington Park on Tuesday with all guns loaded.

Aidan O'Brien's troops are either fully or partly owned by Susan Magnier, the partner of her husband, John Magnier, who owns Coolmore Stud. John Magnier is first and foremost a breeder, and intends to take full advantage of the value inherent in winning any Breeders' Cup race.

ARLINGTON HEIGHTS, Ill. - The odyssey has come full circle, and what a long, strange trip it's been. War Emblem began his career exactly 55 weeks ago at Arlington Park, winning a one-mile maiden race. Saturday, he closes his meteoric career by attempting to secure the title of Horse of the Year in the $4 million Breeders' Cup Classic, highlight of the 19th World Thoroughbred Championships.

ARLINGTON HEIGHTS, Ill. - Veteran Breeders' Cup handicappers have become accustomed to having the Mile as their own little playground. The race typically attracts a wide array of good horses and very good horses, and the odds board offers a smorgasbord of wagering value from top to bottom.

ARLINGTON HEIGHTS, Ill. - Since the Eclipse Awards were inaugurated in 1971, no filly has been named Horse of the Year without beating males. That is the history Azeri will be bucking should she win Saturday's $2 million Breeders' Cup Distaff at Arlington Park.

First, though, she has to win the race. And while Azeri will be a short price to do so, she is part of a deep, talented field, and will have to run hard every step of the 1 1/8 miles to prevail.

ARLINGTON HEIGHTS, Ill. - No race typifies the unpredictability of the $1 million Breeders' Cup Sprint more than last year's edition. Speed demons Squirtle Squirt, Xtra Heat, and Caller One engaged in a furious pace duel over a Belmont racetrack that favored outside closers, but the speedy trio survived the battle to finish first, second, and third respectively, in the six-furlong race.